JPH11220193A - Laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To get a positional angle excellent in oscillation efficiency in a short time, and suppress power consumption, by displacing a laser reflective mirror in order within the range of rotational angle where the laser output can be decided by measurement results, and getting the optimum angle in each axis of the laser reflective mirror from the output. SOLUTION: An output sensor detects the laser output oscillated from a resonator. Then, in case the laser output is not detected, a controller drives pulse motors 18a and 18b, and it makes the first full reflection mirror scan on a vortex, taking the range of the laser output into consideration, and the laser output is detected. Next, when the laser output is detected to some degree, adjustment is performed in the direction of X axis and Y axis, and the positional angle of the first full reflection mirror where the maximum output value of the laser can be obtained is decided. Next, the adjustment of the second full reflection mirror is performed, using a pulse motor 19, and the positional angle where the most efficient laser output can be obtained is decided. Hereby, the laser output excellent in oscillation efficiency can be obtained with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser apparatus for performing treatment by irradiating a treatment laser beam from a laser light source to an affected part by irradiating it with light.

[0002]

2. Description of the Related Art As a conventional laser apparatus, there is known a laser treatment apparatus which irradiates a treatment laser beam to a fundus of a patient's eye to perform photocoagulation or the like. A laser light source used in this type of device is excited in a laser tube, and oscillates laser light by resonating generated laser light with a pair of reflection mirrors provided so as to face each other in parallel with both ends of the laser tube. It has gained. If the reflection mirrors provided at both ends are slightly misaligned, the laser does not oscillate or emit, or the oscillation efficiency deteriorates, causing problems such as a decrease in irradiation output with respect to the set output of the laser. . Therefore, when the power is turned on, the laser is oscillated as an initial setting, and at the same time, the reflection mirror is driven to rotate at the same time. Laser oscillation has been obtained.

[0003]

However, in order to obtain the optimum laser oscillation, it takes a very long time since all of the predetermined pulses are rotated and measured, and the operator must wait for the time.

In addition, the power consumption increases due to the time required, and the amount of heat generated also increases. As a result, the temperature inside the laser device rises, so that the time required to reach a preset use limit temperature is shortened. There was a problem that it was easy to become. In particular, there is a demand for a laser treatment apparatus used for surgery or the like that can suppress the amount of heat generated as much as possible so that the apparatus does not stop during operation due to reaching a use limit temperature.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a laser device which can derive a position angle with good oscillation efficiency in a short time and can reduce power consumption.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) A laser device that oscillates laser light has laser oscillation means for obtaining laser oscillation, and a laser reflection mirror for resonating the laser light oscillated by the laser oscillation means. Resonating means, rotating means for rotating at least one of the laser reflecting mirrors about a first axis and a second axis intersecting the first axis at a predetermined angle, and the laser means; Measuring means for measuring the output value of the laser beam emitted from the reflection mirror; and rotating the laser reflection mirror at least three rotation angles determined based on the output characteristics with respect to angular displacement. The laser output at the rotation angle is measured by the measuring means, and the laser reflection mirror is sequentially displaced within the range of the rotation angle determined based on the measurement result to obtain the output, thereby obtaining the laser reflection. Each of the mirrors Mirror for finding the optimal axial angle
And angle detecting means.

(2) In the laser device of (1), the mirror angle detecting means determines an optimum angle based on an output result when the laser reflection mirror is placed at at least three rotation angles. It is characterized in that it has a predicting means for predicting between the rotation angle and which rotation angle.

(3) In the laser device of (2), the mirror angle detecting means rotates and scans the laser reflection mirror between the rotation angles predicted by the prediction means. It is characterized in that the output with respect to the rotation angle is measured.

(4) In the laser device of (1), the mirror angle detecting means rotationally scans the laser reflection mirror within the rotation angle range around an angle at which the highest output is obtained. It is characterized by the following.

(5) In the laser device of (1), the driving means drives only one mirror of the laser reflection mirror.

(6) In the laser device of (4), the laser oscillating means oscillates laser light having a plurality of main wavelengths, and the driving means is one of the laser reflection mirrors. Characterized in that only the total reflection mirror is driven.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. The laser treatment device used in the embodiment is an ion laser device capable of selecting a plurality of wavelengths. FIG. 1 is a schematic sectional view showing an outline of the resonator. 1
Is an ion laser tube in which a gas medium for laser oscillation is sealed. In this embodiment, a krypton laser (Kr) having oscillation light of red light (647.1 nm), yellow light (568.2 nm), and green light (530.9 nm, 520.8 nm) is used.
Two electrodes, an anode 2 and a cathode 3, are provided at both ends of the ion laser tube 1, and discharge is performed by applying a voltage to the enclosed gas medium.

4 is an output mirror, 5 is a first total reflection mirror,
Reference numeral 6 denotes a second total reflection mirror. The first total reflection mirror 5 has a characteristic of reflecting light of yellow light (568.2 nm) and green light (530.9 nm, 520.8 nm), and is fixedly arranged on the laser optical axis L. The second total reflection mirror 6 emits red light (647.1 nm
), And is disposed on the optical axis L such that it can be inserted and removed. The output mirror 4 has a transmittance of 1 to 3% for light in all wavelength ranges of red light, yellow light, and green light. Therefore, when the second total reflection mirror 6 is arranged on the optical axis L, a resonator is formed by the second total reflection mirror 6 and the output mirror 4, and red laser light oscillates. On the other hand, when the second total reflection mirror 6 is retracted from the optical axis L, a resonator is formed by the first total reflection mirror 5 and the output mirror 4, and yellow light (568.2 nm) is formed.
Also, laser light of green light (530.9 nm, 520.8 nm) is oscillated. For details on laser oscillation of different wavelengths by the switching mechanism of the first total reflection mirror 5 and the second total reflection mirror 6, refer to Japanese Patent Application No. 9-10430.

In order to amplify the laser light, the output mirror 4, the first total reflection mirror 5, the second
It is required that the total reflection mirrors 6 take correct positions, respectively. In this embodiment, the following resonators 7 are formed.

The resonator 7 is composed of three rod rods 8 made of a material having a low coefficient of thermal expansion such as Invar or Super Invar.
(A single rod is not shown in the figure) and plates 9, 10, 11, and 12 connecting the rod 8 form a structure, and the ion laser tube 1 is held by the plates 10, 11. I have. Plates 9 and 12 are provided at both ends of the rod 8, and the plate 9 has a movable plate 13 that holds first and second total reflection mirrors 5 and 6.
A movable plate 14 for holding the output mirror 4 is connected to 2 via a leaf spring. FIG. 2 is a view of the resonator 7 viewed from an oblique direction on the cathode side of the ion laser tube 1. As shown in FIG. 2, the resonator 7 is connected to the leaf springs 15a, 15b, and 15c at three points.

The movable plate 13 is connected with three adjusting screws 16a, 16b and 16c. Similarly, the movable plate 14 uses a leaf spring and an adjusting screw at three locations. Adjusting screws 16a, 1 of the movable plate 13
The pulse motors 18a and 18b are respectively attached to 6b, and the adjustment screws 16a and 16b are moved forward and backward by respectively driving the motors. When the adjusting screw 16a moves back and forth, the movable plate 13 rotates slightly around the adjusting screw 16c around the X axis in FIG. When the adjusting screw 16b moves back and forth, the movable plate 13 rotates slightly around the adjusting screw 16c with the Y axis as a rotation axis. Using this, the first total reflection mirror 5,
The angle position of the second total reflection mirror 6 with respect to the laser optical axis L can be adjusted. The movable plates 13 and 14 are manually adjusted in advance by using adjustment screws at the time of assembling the resonator or at the time of maintenance, so that laser oscillation can be performed at the time of shipment.

Reference numeral 17 denotes a dust-proof cover for protecting the first total reflection mirror 5 and the second total reflection mirror 6 from dust and dirt. A pulse motor 19 is attached to the outside of the dust cover 17, and by using this, the second total reflection mirror can be inserted on the laser optical axis L.

The operation of the apparatus having the above configuration is shown in FIG.
This will be described with reference to the control system schematic diagram of FIG.

When the power of the apparatus body 1 is turned on, the control unit 2
In the case of 0, the shutter sensor 23 checks whether the safety shutter 22 is securely inserted. If the second mirror is securely inserted, the operation of checking whether the second total reflection mirror is properly inserted on the laser optical axis L is checked using the pulse motor 19. After the operation check, the second total reflection mirror 6 is moved to the optical axis L.
After being separated from the top and switched to the first total reflection mirror 5, a predetermined current (30A) is supplied from the laser power supply 24. A predetermined current flows from the laser power supply 24, and the laser oscillates from the resonator 7. The output of the laser at this time is partially reflected by a beam splitter 25 that transmits most of the laser light and reflects part of the laser light, and is incident on an output sensor 26. The output sensor 26 detects the laser output of the laser light oscillated from the resonator 7.

If the laser output is not detected at this time, the control unit 20 controls the pulse motors 18a and 18b.
By driving the adjusting screws 16a and 16b, the position angle of the first total reflection mirror 5 from which the laser output is obtained is determined using the following adjusting method.

FIG. 4 is a diagram showing an adjusting means when the position angle of the total reflection mirror is bad even when the ion laser tube is discharged and laser light does not oscillate. Here, A indicates the initial position of the first total reflection mirror 5. PA is a range indicating the position angle of the total reflection mirror in which the laser can oscillate from the resonator 7, and PT indicates a position angle at which an optimum laser output can be obtained efficiently within the range PA. The optimum laser output efficiently refers to a state where the laser output reaches a maximum value at a predetermined current.

The control unit 20 drives the pulse motors 18a and 18b while supplying a predetermined current, and the first total reflection mirror 5
Is driven in the X-axis and Y-axis directions by 500 pulses as shown in FIG. 4, and a laser output is detected at each point. The number of pulses to be driven at one time is determined in consideration of the range (PA) of the laser output. The first total reflection mirror 5 is swirled to scan, and when it reaches the range PA, the laser is emitted from the resonator 7 and the output sensor 26 detects the laser output.

Next, when the laser output is detected to some extent by the output sensor 26, the control unit 20 operates as follows so that the output value of the laser is maximized at a predetermined current in each of the X-axis direction and the Y-axis direction. The position angle of the first total reflection mirror 5 is determined using an appropriate adjustment method.

First, the control unit 20 controls the pulse motor 18b.
Is used to detect the position where the maximum output value of the laser in the X-axis direction is obtained. FIG. 5 is a diagram showing a laser output distribution with respect to a position angle of the first total reflection mirror 5 with respect to the X-axis direction. Here, PAx indicates the laser output range in the X-axis direction, and PTx indicates the maximum output value of the laser.
The control unit 20 detects the output of the position P <b> 1 at the beginning and stores the output in the output memory 27. Next, after the first total reflection mirror 5 is rotationally driven to the position P2 (500 pulses) driven by a predetermined pulse, the output at the position P2 is detected and stored in the output memory 27. Further position P in the opposite direction
3 is driven by a predetermined pulse (1000 pulses). At this time, the control unit 20 accurately moves the first total reflection mirror 5 to the position P.
After the pulse motor is driven by 1000 + α pulses to rotate to 3, the motor is returned by α again in the reverse direction (backlash). In this way, by always rotating the motor from a predetermined direction, an angular error due to a play of the gear is eliminated, thereby enabling accurate adjustment. First total reflection mirror 5
After rotating and detecting the laser output when the position P3 is reached,
Similarly, it is stored in the output memory 27.

The control unit 20 compares the output values at the three positions stored in the output memory 27 and sets P based on the comparison result.
The position of Tx is detected. Hereinafter, each of the three conditions will be described.

(In the case where the output value of P1 is the highest) Of the output values at the three positions, when P1 is the highest, the shape is as shown in FIG. 5A. Scanning is performed in a range in which the number of moving pulses required during P3 is a majority (in this case, 250 + left and right pulses). Also in this case, the first total reflection mirror 5 is slowly driven from a predetermined direction (the right side in this embodiment) in order to eliminate an error due to play of the pulse motor, and at the same time, the output sensor 27 detects the laser output value. When scanning in the range of 250 + several pulses on the left and right around P1 is completed and the maximum output value PTx is obtained, the control unit 20 moves the first total reflection mirror 5 from a predetermined direction to a position angle at which the maximum output value is obtained. Drive in rotation.

(In the case where the output value of P2 is the highest) Of the output values at the three positions, when P2 is the highest, the shape becomes as shown in FIG. 5B. In the center, a range that is a majority of the number of movement pulses (in this case, the left and right
+ Several pulses). When scanning in the range of 250 + several pulses on the left and right around P2 is completed and PTx is obtained, the control unit 20 drives the first total reflection mirror 5 to rotate to the position angle at which the maximum output value is obtained.

(In the case where the output value of P3 is the highest) When P3 is the highest among the output values at the three positions, a shape as shown in FIG. 5C is obtained. In the center, a range that is a majority of the number of movement pulses (in this case, the left and right
+ Several pulses) to rotate the first total reflection mirror 5 to a position angle at which PTx is obtained.

When the position angle at which the maximum output value of the laser with respect to the predetermined current is obtained on the X-axis is thus determined, the control unit 20 then starts from that position using only the pulse motor 18a in the Y-axis direction. Is performed in the same manner, and the position angle at which the maximum output value PTy (PT) of the laser is obtained is determined. The PT is obtained by determining the position angle of the first total reflection mirror in the X-axis and Y-axis directions.

Next, the control unit 20 uses the pulse motor 19 to insert the second total reflection mirror 6 on the laser beam path L and performs the same adjustment as that of the first total reflection mirror 5 to obtain the most efficient laser output. Is determined. When all the adjustments are completed, the control unit 20 stops supplying the discharge current from the laser power supply 24 to the resonator 7, and ends the initial setting.

The laser output adjusting method in the laser treatment apparatus shown in the above embodiment compares the output values at three positions P1 to P3 and scans a range centered on the highest output value. Although the position angle of the reflection mirror has been determined, it can be adjusted as follows.

After measuring the laser output at P1 to P3, the output values at P2 and P3 are compared. In the case of P3> P2 (FIGS. 5a and 5c), since PTx is always between P1 and P3, PTx can be determined by scanning from P3 to P1. When P3 <P2 (FIG. 5B), PTx
Is located between P1 and P2, PTx can be determined by scanning from P1 to P2.

In this embodiment, an ion laser tube is used. However, the present invention is not limited to this. A reflection mirror is attached to both ends of the laser tube for causing optical resonance, and laser light is emitted by causing resonance. If possible, it can be implemented.

Further, the positions of P2 and P3 in this embodiment are as follows:
It takes 500 pulses left and right around the position P1,
The range is not limited as long as the position where the efficient laser emission can be obtained in the above-described method is determined.

Further, in this embodiment, only the total reflection mirror is driven. However, by driving only the output mirror on the opposite side or driving two reflection mirrors at the same time, a laser output with good oscillation efficiency can be obtained with high accuracy. Can get well.

[0037]

As described above, according to the present invention,
Since the entire range of the reflection mirror position angle for laser output is not scanned, it is possible to detect the position angle at which a laser output with good oscillation efficiency can be obtained in a short period of time, thereby reducing power consumption and preventing unnecessary heat generation. it can.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a resonator according to an embodiment.

FIG. 2 is a perspective view of the resonator of the embodiment when viewed from an oblique direction on the cathode side of the ion laser tube.

FIG. 3 is a diagram showing a schematic configuration around a control system and a resonator of the device.

FIG. 4 is a diagram illustrating an adjusting unit when laser light does not oscillate.

FIG. 5 is a diagram showing a laser output distribution in an X-axis direction.

[Explanation of symbols]

 Reference Signs List 1 ion laser tube 4 output mirror 5 first total reflection mirror 6 second total reflection mirror 13 movable plate 14 movable plate 15a leaf spring 15b leaf spring 15c leaf spring 16a adjustment screw 16b adjustment screw 16c adjustment screw 20 control unit 22 safety shutter 26 Output sensor

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H01S 3/02 H01S 3/02 Z

Claims (6)

[Claims] 1. A laser device for oscillating laser light, comprising: a laser oscillating means for obtaining laser oscillation;
A resonance means having a laser reflection mirror for resonating the laser light oscillated by the laser oscillation means, and at least one of the laser reflection mirrors of the resonance means at a predetermined angle with respect to the first axis and the first axis. Rotation means for respectively rotating about the intersecting second axes; measuring means for measuring the output value of the laser light emitted from the laser reflection mirror; and output means for the angular displacement. The laser reflection mirror is rotated by at least three rotation angles, the laser output at each rotation angle is measured by the measuring means, and the laser is reflected within a range of the rotation angle determined based on the measurement result. The reflection mirror
And a mirror angle detecting means for obtaining an output of the laser reflecting mirror to obtain an optimum angle in each axial direction of the laser reflection mirror. 2. The laser device according to claim 1, wherein said mirror angle detecting means is provided with at least three rotation angles.
A laser device having a predicting means for predicting which rotation angle is the optimum angle between the rotation angles based on the output result when the reflection mirror is placed. 3. The laser device according to claim 2, wherein said mirror angle detecting means rotates and scans said laser reflection mirror between rotation angles predicted by said prediction means. A laser device for measuring an output with respect to an angle. 4. The laser apparatus according to claim 1, wherein said mirror angle detecting means is provided in said laser reflection mirror within a range of said rotation angle around an angle at which the highest output is obtained.
A laser device that performs rotational scanning of a laser beam. 5. The laser device according to claim 1, wherein said driving means drives only one mirror of said laser reflection mirror. 6. A laser device according to claim 4, wherein said laser oscillation means oscillates laser light having a plurality of main wavelengths, and said driving means includes one of said laser reflection mirrors. A laser device characterized by driving only a total reflection mirror.